Make invisible gravitational waves, radio waves, sound waves, etc., graspable and more comprehensible with AR (Augmented Reality) robotics using a simple device I invented at the age of 12, in 1974. This device is so simple that a child can build it, yet by combining it with robotics, it can provide a true 3D augmented reality display that does not require any special eyeglasses to see.
In this Instructable we'll take this simple device, which is simply linear array of light sources that displays a physical quantity (a previous Instructable showed how to make one), and animate it using robotics. Some very simple robotics you can make from found objects, will move the device in a controlled fashion. It is this control that allows for repeatability, and repeatability is what makes waves and other periodic patterns visible through Persistence of Exposure (to the human retina or to photographic recording media).
Gravitational waves are invisible, intangible, and difficult to understand, but I wanted a way to teach my children about this important contribution to physics. To make the waves visually comprehensible I decided to add to them their Hilbert Transform times the square root of negative one, so that the energy in the signal, rather than rapidly disappear and reappear, slowly varies with time, making more visible the underlying energy envelope.
I worked with my children and my graduate students, as well as undergraduate students at the University of Toronto to assemble a team, and we reached out to the LIGO group at my alma mater (MIT), and also obtained data from the LIGO sites, to work with.
Teaching and teambuilding:
This has been a great team-building project, and projects like this represent a really good teaching opportunity, with exemplary teambuilding as follows:
I proposed the spinning SWIM idea to students in my ECE516 class, and Anshuman (a student in the class) wrote a 3D visualizer to visualize what the spinning SWIM would look like. Marc and I also built some ARbotics systems, and Max came up with some 3D printed designs. Pictured above are Ken, Max, myself, Anshuman, Sarang, Nitin, Adnan, and Pete, also working on the project; Pete and Sarang are doing ongoing work on SWIM, and the two Alexanders also worked on the SWIM. Stephen and Helton (not pictured above) helped in some of the earlier photographic capture of this project. Sarang, Adnan, and Nitin, are working on using the Chirplet Transform to represent gravitational waves; you can clearly see that the signal here takes the form of a chirplet. In the same way that a wavelet is a piece of a wave, a chirplet is a piece of a chirp, i.e. a localized (windowed) chirp.
Together we built a simple robot that moves a SWIM (Sequential Wave Imprinting Machine) in a simple controlled pattern, allowing it to imprint the gravitational waves onto the human retina or onto photographic film using PoE (Persistence of Exposure). See my earlier Instructables on SWIM and on Phenomenal Augmented Reality using a simple light bulb or LED.
This Instructable will introduce Augmented Reality robotics ("ARbotics"): robotics combined with the phenomenological persistence of exposure principle, to make waves tangible and thus more teachable to children as well as adults alike.
(Rails as a form of visual art: here's 3 photos I took near the railway tracks in the town of Dundas, Ontario, in the 1980s, one of which was used as a full page ad in Impulse Magazine: visualization of circularly polarized radio waves with Sequential Wave Imprinting Machine.)
I've always had a childhood fascination with railway tracks, as a way of guiding my arrays of light sources through a straight or gently curved spacetime continuum. Walking along the tracks with the SWIM during a long exposure photograph, I could plot out or map out a physical reality along a smooth trajectory. I also grew up with model railway and toy racecar (slotcar) sets, which I also used as a basis for creating phenomenological augmented reality systems.
I used to sometimes build small railcars and other objects for use on real train tracks, e.g. to push along one of the tracks, or sometimes something a little bigger that would straddle both tracks. In 1984 my parents moved to a new house that was located directly beside a beautiful set of railway tracks that defined the border between the towns of Ancaster and Dundas, so I immediately intensified this work through a series of phenomenological augmented reality photographs.
But you don't need railway tracks to make phenomenal augmented reality SWIMbots, you just need a small model railroad or toy racecar or toy slotcar, and even if you don't have any of those, a simple straight or gently curved piece of wood or metal will do. You can even use the edge of a desk, and you can make a simple "railcar" out of an L-shaped wooden block that slides along the edge of the desk!